Statins for preventing blood clot formation within veins

Background

Venous thrombosis or thromboembolism (VTE) is a condition in which a blood clot (thrombus) forms in a vein and causes a blockage. The blockage most commonly occurs in the 'deep veins' of the lower legs, thighs or pelvis and is called deep vein thrombosis (DVT). If part of or the entire clot breaks away and is carried through the blood (venous) system it is called an embolism. Should the clot reach the lungs, it is known as a pulmonary embolism (PE) and is life threatening. VTE affects about 3,705,000 people worldwide annually and is one of the most preventable causes of hospital deaths. Statins are well known cholesterol-lowering drugs that are used in heart disease. They have other protective effects including anti-clotting properties and may be effective in the prevention of VTE. The objective of this review was to assess the efficacy of statins in the primary prevention of VTE.

Key results

Our review included one published randomised controlled trial, involving 17,802 participants, which reported outcomes of VTE. This trial investigated rosuvastatin compared with placebo for the primary prevention of VTE. Analysis showed that, compared with placebo, rosuvastatin reduced the incidence of VTE and DVT, the risk of any (fatal and non-fatal) myocardial infarction, and any (fatal and non-fatal) stroke. There were no differences between rosuvastatin and placebo in the incidence of pulmonary embolism, fatal myocardial infarction, fatal stroke, and death after VTE. The incidence of any serious adverse events was not different between rosuvastatin and placebo. No firm conclusions or suggestions could be made from these findings. More randomised controlled trials of statins (including rosuvastatin) are needed to evaluate the efficacy of statins in the prevention of VTE.

Quality of the evidence

The quality of the evidence was moderate because of imprecision, as the required sample size for the outcomes of this review was not achieved.

Authors' conclusions: 

Available evidence showed that rosuvastatin was associated with a reduced incidence of VTE, but the evidence was limited to a single RCT and any firm conclusions and suggestions could be not drawn. Randomised controlled trials of statins (including rosuvastatin) are needed to evaluate their efficacy in the prevention of VTE.

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Background: 

Venous thromboembolism (VTE) is common in clinical practice. The efficacy of statins in the primary prevention of VTE remains unproven. This is an update of the review first published in 2011.

Objectives: 

To assess the efficacy of statins in the primary prevention of VTE.

Search strategy: 

For this update the Cochrane Peripheral Vascular Diseases (PVD) Group Trials Search Co-ordinator searched the Specialised Register (last searched February 2014) and CENTRAL (2014, Issue 1).

Selection criteria: 

Randomised controlled trials (RCTs) that assessed statins in the primary prevention of VTE were considered. The outcomes we evaluated were the rates of VTE, cardiovascular and cerebrovascular events, death and adverse events. Two authors (L Li, JH Tian) independently selected RCTs against the inclusion criteria. Disagreements were resolved by discussion with a third author (KH Yang).

Data collection and analysis: 

Data extraction was independently carried out by two authors (L Li, JH Tian). Disagreements were resolved by discussion with a third author (PZ Zhang). Two authors (L Li, JH Tian) independently assessed the risk of bias according to a standard quality checklist provided by the PVD Group.

Main results: 

For this update we included one RCT with 17,802 participants that assessed rosuvastatin compared with placebo for the prevention of VTE. The quality of the evidence was moderate because of imprecision, as the required sample size for the outcomes of this review was not achieved. Analysis showed that when compared with placebo rosuvastatin reduced the incidence of VTE (odds ratio (OR) 0.57, 95% confidence interval (CI) 0.37 to 0.86) and deep vein thrombosis (DVT) (OR 0.45, 95% CI 0.25 to 0.79), the risk of any (fatal and non-fatal) myocardial infarction (MI) (OR 0.45, 95% CI 0.30 to 0.69), and any (fatal and non-fatal) stroke (OR 0.51, 95% CI 0.34 to 0.78). There was no difference in the incidence of pulmonary embolism (PE) (OR 0.77, 95% CI 0.41 to 1.46), fatal MI (OR 1.50, 95% CI 0.53 to 4.22), fatal stroke (OR 0.30, 95% CI 0.08 to 1.09) or death after VTE (OR 0.50, 95% CI 0.20 to 1.24). The incidence of any serious adverse events was no different between the rosuvastatin and placebo groups (OR 1.07, 95% CI 0.95 to 1.20).

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